[Coco] Re: [Color Computer] Re: Dragon Disk interface

[Phill Harvey-Smith]

Gene Heskett wrote:
> On Sunday 27 March 2005 22:29, Phill Harvey-Smith wrote:
> 
>>Gene Heskett wrote:
>>
>>>On Sunday 27 March 2005 17:48, Phill Harvey-Smith wrote:
[Snip, to keep the length down :)]
>>Hope that wasn't too technical :)
 >
> Not at all Phill, thanks.  

No probs.

 > One thing I didn't see mentioned was the
> data rate the 2797 can run at.  I don't have any data sheets on it 
> here.  Can it do 500 kilobaud and maybe even 1 megabaud?  

It will do 500Kbaud, as it was designed to also work with 8" disks which 
IIRC work at this data rate.

>I'm 
> thinking in terms of 1.2 meg and even 2.4 or 2.88 meg disks in the 
> usual 3.5" drive for those drives that can support the original I've 
> Been Moved 2.88 disks.  Probably not many of those left in 
> circulation though.

I have had one version of my development board reading 1.44MB PC disks, 
needed to use the speed up poke to enable the Dragon to keep up with the 
data rate tho.

> Also, since that chip has probably been EOL'd for a decade now, how 
> are supplies?  More recent, and possibly more capable clones even 
> should be considered. 

Managed to get hold of 5 of them last year as new old stock, just as 
spares for my real DragonDos cart, and for projects like this. Main 
benifit is that they are compatible from a software pov, to the 1793/1773.

>			 There was one in common useage on many of the 
> older wintel motherboards back before it all got integrated that was 
> quite versatile, but I don't recall its part number now.

Off the top of my head I can't say I can either, but I do know the one 
you mean.

> I do see, in the present linux floppy driver that has to handle 
> everything that comes down the pike, has formats to as high as 3.84 
> megabytes on a 3.5" drive.  But I don't see a lot of chip specific 
> stuff there, so maybe I'm looking at the wrong driver src file.

Have not dug around in the Linux kernel much, but yeah should be in
there as the modern integrated chipsets also emulate it.

Phill.


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